Artemisinin, of formula

is an active ingredient of plant origin which was isolated in 1972 from the leaves of Artemisia annua L., a shrub which had long been used in Chinese traditional medicine to treat fever and malaria. Due to its ability to interfere with the regulation of the genes involved in the control of cell proliferation, angiogenesis and apoptosis, Artemisinin has also proved active in the treatment of uveal cancer at nanomolar concentrations, with toxicity comparable to that of conventional antitumoral drugs. A semisynthetic derivative of Artemisinin, Artesunate,

obtained by reduction of the ketone group at the 12-position of Artemisinin and subsequent esterification with succinic acid, is used either alone or in association with other malaria drugs, but has also proved effective in the treatment of metastatic uveal melanoma in association with standard chemotherapy.
Some Artemisinin derivatives are also known, such as 12-dihydroartemisinin, dihydroartemisinin 12-benzoate, 12-(2′-hydroxyethyl)deoxyartemisinin, the 12(2′-ethylthio) dimer of deoxyartemisinin and the trimer of deoxyartemisinin. This latter compound, in particular, has a powerful antitumoral effect (CI50=6.0 μM), even greater than that of paclitaxel (CI50=13.1 μM), on the cell line of oral cancer (YD-10B); it also induces apoptosis through a caspase-3-dependent mechanism.
It would be therefore advantageous to have further Artemisinin derivatives which possess improved antitumoral activity.